The motor on both bikes is the same
I just replaced my Specialized tires from Gatorskins to Conti GP 5000s. After 2 rides on the trail in question, i beat my PR once by 15 secs with the Specialized but with a fair amount of effort. The best time I set with the Trek, I didn't feel nearly as gassed. I realize things are different day to day, temperature, wind, etc. but I'm taking that into account on the times I've set on the rides. We've had some really calm, windless days here in Nebraska lately so I'm comparing similar days and weather. The GP 5000s seem to have really helped, but I still can't get over how both bikes roll so differently. The trek just seems/feels like it rolls fast and free, whereas the specialized almost feels like something is always slowing it down like a rubbing brake pad, but I've checked and it's not the case. I also just got new hubs, full tune and everything appears in top shape on the Specialized.